Aqueous compositions containing imidazolinyl acid salts are described in U.S. Pat. No. 4,816,060, and aqueous compositions containing glyphosate salts are described in EP 220,902-A2. However, concentrated, aqueous compositions comprising an imidazolinyl acid salt and a glyphosate salt have not been described. The principal reason that aqueous compositions containing both of those compounds have not been disclosed is that imidazolinyl acid salts and glyphosate salts are, in general, not mutually compatible. Aqueous glyphosate salt compositions generally have a pH value of about 4. However, imidazolinyl acid salts are not entirely stable in an environment having a pH value of about 4. Conversely, glyphosate salts are not entirely stable at the pH values required to provide stable aqueous compositions of imidazolinyl acid salts.
To overcome the incompatibility problems associated with aqueous compositions containing imidazolinyl acid salts and glyphosate salts, emulsifiable suspension concentrate compositions containing imidazolinyl acids and glyphosate have been described (see, e.g., U.S. Pat. No. 5,268,352). However, emulsifiable suspension concentrate compositions are not entirely satisfactory because they require the use of heavy aromatic solvents.
What is needed in the art is an aqueous composition which overcomes the incompatibility problems associated with imidazolinyl acid salts and glyphosate salts without requiring the use of heavy aromatic solvents.
It is, therefore, an object of the present invention to provide a concentrated, aqueous herbicidal composition which contains an imidazolinyl acid salt and a glyphosate salt.
It is also an object of the present invention to provide a process for the preparation of a concentrated, aqueous herbicidal composition which contains an imidazolinyl acid salt and a glyphosate salt.
Those and other objects of the present invention will become more apparent from the detailed description thereof set forth below.